At present there are no industrial processes that recover magnesium and other reactive elements from aluminum (Al) or magnesium (Mg) alloys for production of primary-quality alloys. Current practices to refine Al alloy melt use chlorination with gas mixtures or reactive salts and transfer reactive alloying elements from the Al alloy into dross for disposal.
The present invention relates to a density-based three-liquid electrorefining process to continuously extract primary-quality Mg—Al or Al—Mg alloys from molten Al scrap acting as feedstock for secondary Al-alloy. The chemical composition of both the Al scrap feedstock as well as the Al—Mg alloy products may be variable depending on scrap supply, product demand and cost. The electrorefining can selectively transfer Mg from Al—Mg alloy bottom layer to Mg—Al alloy floating top layer.